Patent Application
20050111949
The present invention generally relates to devices for lifting and towing vehicles by a pair of the vehicle wheels, known as wheel lifts. More particularly, the invention is directed to a self-loading wheel lift that may be rapidly disassembled for transportation or repair and/or rapidly converted or transformed for other applications.
Commonly assigned U.S. Pat. Nos. 4,637,623 and 4,798,509 to Alm, each entitled “Towing Apparatus,” and U.S. Pat. No. 4,836,737 to Holmes entitled “Wheel Lift Tow Assembly,” each disclosing known wheel lift assemblies, as well as U.S. Pat. No. 4,564,207 to Russ et al., entitled “Hydraulic Wheel Lift System For Tow Vehicles,” are each hereby incorporated by reference in their entirety into this application.
For years the standard hydraulic self-loading wheel lift, such as depicted in U.S. Pat. No. 4,564,207 to Russ et al. has enjoyed a specific usage in the towing industry. While capable of automatically loading automobiles in seconds with ease and permitting operators to remain in the safe environment of their cab, self-loading wheel lifts can only load those automobiles possessing tires. Such wheel lifts are also limited by their inability to handle the weight of larger trucks and the like. The typical assembly of such wheel lifts includes a cross bar roughly 80 inches long for capturing the towed vehicle's tires. Two wheel support members such as L-shaped arms may be pivotally attached to the cross bar, swinging from inside and then outwardly to capture a towed vehicle's tires. Hydraulic cylinders, for example, may power L-arm movement. In the past, the wheel support members of self-loading wheel lifts have not been designed to be removed from the cross bar.
Conventional wheel lifts are also an industry standard and have been in the towing industry for years. These wheel lifts, exemplified by those disclosed in U.S. Pat. Nos. 4,637,623, 4,798,509 and 4,836,737, are more versatile than self-loading wheel lifts in some ways, as they are capable of loading vehicles with or without tires, as well as heavier vehicles such as heavy trucks. However, the process required to engage a towed vehicle using a conventional wheel lift is considerably longer than with a self-loading wheel lift, and may take ten minutes or longer. In addition, the tow truck operator must exit the cab to manually place the L-arms or other tow-engaging attachments, exposing him to the elements and traffic. The typical assembly of a conventional wheel lift includes a cross bar roughly 40-60 inches in length. Two shoes are slid over opposing ends of the cross bar, and pivoting collars may be mounted to the shoes. The collars engage L-arms that are manually placed to engage the tires or other locations on a towed vehicle. The L-arms are designed to engage points on the towed vehicle from the outside in, limiting their ability to engage tires located adjacent curbs, for example. While some conventional wheel lifts may be converted from using L-arms to a tool bar, the conversion has been manual and time-consuming, and the L-arms were unable to swing from the inside out, limiting their application.
Self-loading or conventional wheel lift assemblies have not been previously designed, to applicant's knowledge, to permit rapid disassembly in the field or to allow rapid conversion to an alternate towing mechanism. Often, the cross bar of wheel lift-type tow mechanisms includes shoes or brackets that are welded to the ends of the cross bars. Additionally, the presence of permanently attached powering mechanisms such as hydraulic cylinders may render it difficult and time-consuming to remove wheel support members and/or receivers from the cross bar. In short, it is not believed that self-loading wheel lifts have been designed with the ability to rapidly convert or transform the wheel lift device into an alternate towing mechanism, such as a tool bar or frame fork attachment.
Accordingly, it would be advantageous to provide a self-loading wheel lift that overcomes the current disadvantages of such wheel lifts, while providing new advantages.
The following terms are used in the claims of the patent as filed and are intended to have their broadest meaning consistent with the requirements of law. Where alternative meanings are possible, the broadest meaning is intended. All words used in the claims are intended to be used in the normal, customary usage of grammar and the English language.
“Self-loading wheel lift” refers to a wheel lift capable of engaging and lifting a towed vehicle without the necessity of manually placing wheel support members to engage the towed vehicle.
“Tool bar” means a round or square tube connected to the rear of a towing vehicle and able to receive various attachments to effectuate or facilitate towing a vehicle such as but not limited to hook ends, frame forks, slings, pintle hooks, fifth-wheel plates, king pins, etc.
“Wheel lift” means any device designed to lift and tow vehicles by attachment to and sole or substantial support by the wheels of the towed vehicle.
The objects mentioned above, as well as other objects, are solved by the present invention, which overcomes disadvantages of prior wheel lifts, while providing new advantages not believed associated with such devices, including those advantages listed above as well as other advantages as well.
The self-loading wheel lift of the present invention may be rapidly disassembled and converted or transformed into an alternate towing mechanism. In one embodiment, the receiving tubes and L-arms may be slid off opposing ends of the cross bar as one unit, allowing the operator/driver of the towing vehicle to rapidly convert the device from a self-loading wheel lift to a towing mechanism having rearwardly engaging tool bar or frame fork attachment in a matter of seconds. This allows the tow truck the flexibility to tow heavier vehicles, while also retaining the abilities of a self-loading wheel lift whose L-arms can swing from the inside out using (e.g.) hydraulic cylinders.
In one preferred embodiment, an apparatus is provided for use in a lifting and towing vehicle. A boom may extend rearwardly from the lifting and towing vehicle, and a powered actuator, such as one or more hydraulic cylinders, may be used to move the boom into different angular orientations relative to horizontal. A transverse support beam or cross bar may be connected to the end of the boom. The cross bar may be positioned below a towable vehicle, and includes two opposing end portions. The end portions may be horizontally moveable relative to the cross bar, and each end is capable of being positioned adjacent to one of a pair of wheels on the towable vehicle. Two receivers are each removably connected to opposing end portions of the cross bar. Each receiver carries a wheel support member, which may but need not be an L-arm having an elongated arm and a wheel engaging end such as a wheel retainer. The wheel support members are capable of being swung back and forth in a generally horizontal plane. One or more powering mechanisms, such as hydraulic cylinders, pneumatic cylinders, electric motors/solenoids, etc. preferably drive movement of the wheel support members in the generally horizontal plane. The receivers with the wheel support members form a wheel lift apparatus which may be rapidly disassembled from the cross bar in the field to permit conversion from the wheel lift apparatus to an alternate towing apparatus, such as but not limited to a tool bar employing frame fork attachments, hook ends, slings, pintle hooks, fifth-wheel plates, king pins, etc.
Preferably, the wheel support members may be rotated in a generally horizontal plane from a position inside the tires of the towable vehicle to a wheel engaging position.
Mechanisms, such as cam locks, bolts, pins, wire, etc. may be employed to facilitate rapid connection and decoupling of each wheel lift apparatus (i.e., the receiver/wheel support member set) from the cross bar. For example, a cam lock with a rotatable handle and a spring-loaded plunger pin may be used to quickly connect and disconnect the receiver from the cross bar. The cylinder rod connection point may also need to be connected or disconnected as well. For this purpose, the distal ends of each cylinder rod may include an aperture for use in coupling each cylinder rod to a receiver. Alternatively, each cylinder rod may consist of two component rods that are connected to each other, e.g., one may be slidable within the other and they be attached using a removable locking pin allowing rapid field disassembly. Preferably, the wheel support members are pivotally attached to the receivers using a pivot pin, for example, which may be prevented from accidental disengagement by use of a retaining mechanism, such as a counter-sunk screw. Parallel plates, lying above and below the cross bar, may but need not be used to facilitate attachment of each wheel support member to the receivers.
In an alternative embodiment of the present invention, a method is provided for use in lifting and towing vehicle. A boom carrying a transverse support beam or cross bar may first be positioned adjacent a towable vehicle. The support beam may be positioned below the towable vehicle. The support beam may include two opposing end portions mounted by removably connected receivers. Each receiver may carry or support a wheel support member, which may include an elongated arm and a wheel engaging member. The wheel support members may be pivotally connected to the receivers and may be capable of being swung back and forth in a generally horizontal plane. The receivers and wheel support members together form the wheel lift apparatus. Next, a wheel engaging portion of each wheel support member may be positioned adjacent and between each of a pair of wheels of the towable vehicle. The wheel engaging portions may then be caused to rotate outwardly toward the wheels of the towable vehicle into a wheel engaging position. One or more powering mechanisms, such as hydraulic cylinders, may be used to drive movement of the wheel support members in the generally horizontal plane. The now wheel-engaged and towable vehicle may now be lifted and towed to a desired location, where the towable vehicle may be disengaged. If desirable, the lifting and towing vehicle may be converted in the field by rapidly disassembling the wheel lift apparatus from the support bar and replacing it with an alternate towing apparatus, such as a tool bar employing various types of attachments.
The novel features which are characteristic of the invention are set forth in the appended claims. The invention itself, however, together with further objects and attendant advantages thereof, will be best understood by reference to the following description taken in connection with the accompanying drawings. The drawings illustrate currently preferred embodiments of the present invention. As further explained below, it will be understood that other embodiments, not shown in the drawings, also fall within the spirit and scope of the invention.
Set forth below is a description of what are currently believed to be the preferred embodiments and/or best examples of the invention claimed. Future and present alternatives and modifications to these preferred embodiments are contemplated. Any alternatives or modifications which make insubstantial changes in function, in purpose, in structure or in result are intended to be covered by the claims of this patent.
Referring first to
Wheel lift apparatus 20 may be attached to cross bar 30 using receivers, such as receiving tubes 35, which may be slid over opposing ends of cross bar 30 as shown, and fastened in place using cam-lock 40 and/or other mechanisms, as further described below. Wheel lift 20 may include wheel support members for engaging the tires of a vehicle to be towed, such as a pair of jaws or L-arms 50. Each L-arm 50 may include a leg 51, which may be generally perpendicular to cross bar 30, and a wheel engaging leg 52 which may be generally parallel to the cross bar.
L-arms 50 are preferably pivotally mounted to receivers 35 to allow the L-arms to swivel in a horizontal plane, as best shown in
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It will now be understood that wheel lift 20 may be rapidly assembled and disassembled in the field such that receivers 35, carrying L-arms 50, may be removed from cross bar 30, and replacement towing mechanisms may then be attached to cross bar 30 via a tool bar, for example. For example, referring to
It will be understood that self-loading wheel lifts with alternative functions may be designed according to the principles of the present invention. For example, movement of wheel support members may be powered using alternative mechanisms other than hydraulic cylinders, such as pneumatic cylinders, electric motors/solenoids, chains, rope, etc. Preferably, however, self-loading wheel lifts according to the present invention retain the ability to engage a towed vehicle's wheel from the inside out, and retain the rapid disassembly and conversion capability.
The above description is not intended to limit the meaning of the words used in the following claims that define the invention. Rather, it is contemplated that future modifications in structure, function or result will exist that are not substantial changes and that all such insubstantial changes are intended to be covered by the following claims.
